ABSTRACT
M.bovis BCG vaccination against tuberculosis (TB) notoriously displays variable protective efficacy in different human populations. In non-human primate studies using rhesus macaques, despite efforts to standardise the model, we have also observed variable efficacy of BCG upon subsequent experimental M. tuberculosis challenge. In the present head-to-head study, we establish that the protective efficacy of standard parenteral BCG immunisation varies among different rhesus cohorts. This provides different dynamic ranges for evaluation of investigational vaccines, opportunities for identifying possible correlates of protective immunity and for determining why parenteral BCG immunisation sometimes fails. We also show that pulmonary mucosal BCG vaccination confers reduced local pathology and improves haematological and immunological parameters post-infection in animals that are not responsive to induction of protection by standard intra-dermal BCG. These results have important implications for pulmonary TB vaccination strategies in the future.
Subject(s)
BCG Vaccine/administration & dosage , Immunogenicity, Vaccine , Mycobacterium tuberculosis/immunology , Tuberculosis/prevention & control , Vaccination , Administration, Inhalation , Animals , BCG Vaccine/toxicity , Disease Models, Animal , Female , Immunity, Mucosal , Injections, Intradermal , Macaca mulatta , Male , Mycobacterium tuberculosis/pathogenicity , Respiratory Mucosa/immunology , Respiratory Mucosa/microbiology , Time Factors , Tuberculosis/immunology , Tuberculosis/microbiologyABSTRACT
PURPOSE: Consumption of undercooked pork meat products has been considered a major risk factor for contracting toxoplasmosis in humans. Indoor farming and improved hygiene have drastically reduced Toxoplasma infections in pigs over the past decades. Whether introduction of animal-friendly production systems will lead to a reemergence of Toxoplasma infections in pigs is not yet known. Investigating this possibility was the purpose of this study. METHODS: Blood was obtained from pigs raised for slaughter and tested for Toxoplasma antibodies by using latex agglutination and indirect immunofluorescence testing, with confirmation by immunoblotting. RESULTS: None of the slaughter pigs (n = 621) from conventional farms (n = 30) were positive, whereas 38 (2.9%) of 1295 animals from animal-friendly systems tested positive (n = 33 farms; 13 [39%] farms positive). CONCLUSIONS: The following conclusions may be derived from this study: Conventionally (indoors) raised pigs are free from Toxoplasma infection, and (2) animal-friendly production systems may lead to a reemergence of Toxoplasma infections, although many of these farms remain Toxoplasma free. Slaughterhouse monitoring of pigs from animal-friendly production systems combined with on-farm prevention strategies should be applied to ensure safety for consumers of the meat products obtained from these animals.
